Fixing element adapted to be manually pushed into position for fixing insulating strips or plates on a solid substructure

ABSTRACT

This invention relates to a fixing element ( 1 ) for fixing insulating strips ( 5 ) and optionally, additional sealing strips ( 6 ) on a solid substructure ( 7 ). A screw ( 4 ) and a large-surface washer ( 2 ) with a tubular extension ( 3 ) are used. A rib ( 15 ) that projects radially inward into the displacement area is provided in a partial section of the tubular extension ( 3 ), which accommodates a screw bead ( 11 ) in such a way that it is axially displaceable. After passing the rib ( 15 ) in the direction of the free end of the tubular extension ( 3 ), the screw head ( 11 ) can rest on the rib in the direction opposite to the screwing-in direction.

BACKGROUND

The invention relates to a fixing element for fixing insulating stripsor plates and optionally additional sealing strips on a solidsubstructure.

Such fixing elements, as well as their availability in a preassembledstate, are already known in many varied configurations. In a preassemblyof the fixing elements, the screws are inserted in the fixing elements.Then, the fixing elements are processed by means of automatic settingmachines, in which a screwdriver bit directly provides the axial advanceof the screw as well as the insertion of the fixing element into aroofing strip.

BRIEF SUMMARY OF THE INVENTION

In relatively small roofing structures or during the fixing ofinsulation strips or plates, it is desirable that the fixing elements bepre-inserted by hand in a preassembled state, i.e. pushed by hand intothe insulating strips or plates and optionally into additional sealingstrips. Such pushing-in can also be advantageous when it is followed byprocessing with a setting machine.

One embodiment of the fixing element of the present invention is adaptedfor use with a screw which is provided with a thread over at least aportion of the length of its shaft and which has a screw head. Thefixing element preferably includes a large-surface area washer having atubular extension that defines a passage for receiving the screw. Thetubular extension includes at least one rib to preferably allow thefixing element and screw to be pushed into insulation.

The object of the present invention is to substantially improve thehandling potential during pre-insertion of a fixing element of thepreviously described kind.

In accordance with the invention, this is achieved by providing, in thesegment of the tubular extension for axially displaceable reception ofthe screw head, at least one rib which protrudes radially inward intothe displacement region, or one or more burls or the like, against whichthe screw head can abut after surmounting the ribs, burls or the like ina direction which is opposite to that of the screwing-in directiontoward the free end of the tubular extension.

The screws are preassembled in a tubular extension of the large-areawasher by pushing-in the screw head past an appropriate obstacle (rib,burl or the like), whereby the rib, burl or the like forms an abutmentfor pushing the completed fixing element into insulating strips orplates and potentially also into sealing strips. Due to the large-areawasher, there is available a relatively large hand-hold for mounting thefixing element, and that is so independently of whether insertion is byhand or by means of a setting tool, so that the force transfer, duringpushing into the insulating strips or plates and optionally additionallyinto sealing strips, can be carried out without any problem.Nevertheless, there is the assurance that the screw cannot move all theway into the tubular extension, but rather encounters a limiting memberin the form of a rib, a burl or the like. Even with relatively forcefulpushing-in of the preassembled fixing element, the force exerted uponthe large-area washer is transmitted by the rib, burl or the like to thescrew head and thereby to the inserted screw. This also ensures that theboring or penetrating tip formed at the free end of the screw alwayslies at the most forward point of the preassembled fixing element,whereby the pre-insertion of the fixing elements is facilitated.

One kind of embodiment contemplates that the rib, burl or the like isformed near the mid-range of the length of the tubular extension. By sodoing, the screw can slide axially inside the tubular extension over arelatively wide range, which creates a telescopic effect. A telescopiceffect is especially appropriate for use of the fixing element in theroof area, i.e. when walk-on surfaces are to be provided with suchfixing elements. When stepping on such a fixing element, the large-areawasher with the tubular extension can move downwardly in the axialdirection and then back again into the initial position, through theelastic action of the insulating strips or plates.

A preferred embodiment is one in which there is provided an annular ribextending around the entire inside wall. In a preassembly, this rib cannot be easily surmounted, because the preassembly of large-area washershaving tubular extensions and screws is usually performed withappropriate assembly tools which provide the required force. If thefixing elements are then pre-inserted by hand, there exists theassurance that the screw head can no longer surmount the completeannularly closed rib, i.e. a firm abutment exists.

It is preferable that the spacing of the rib, burl or the like from thefree end of the tubular extension is less than the overall length of thescrew including a boring portion formed at its free end. This providesassurance that, in the condition in which the screw head abuts againstthe rib, burl or the like, the free end of the screw and especially itsboring portion still always protrudes beyond the free end of the tubularextension. This substantially facilitates penetration by the fixingelement during pre-insertion.

It also contributes to simple mounting capability and optimal abuttingduring pre-insertion, if the screw head is lens-shaped and itstransition to the shaft has a truncated cone shape. In such a case, itis possible during preassembly to easily push the screw head over theprojecting rib, burl or the like. Nevertheless, the lens-shapedconfiguration of the top of the screw head assures an optimal abutment.

The configuration of the preassembled fixing elements, in accordancewith the invention, creates the additional possibility that severalwashers having a tubular extension which are contiguous to each other,or which follow each other closely, are connected to each other by websor tapes into a kind of screw strip. This makes it substantially easierfor transportation and pre-insertion at the construction site. In thisconnection, the joined-together washers can also be made so as to berelatively easy to separate from each other.

In theory, it is conceivable that the respective screws can be mountedin the tubular extension of the washers just before pre-insertion.Preferably, however, the screws are already preassembled in the tubularextensions of the large-area washers, i.e. each screw head is alreadypushed in past the rib, burl or the like at the internal limit of thetubular extension, so that the rib, burl or the like serves as abutmentfor the screw head. By such preassembly, loss prevention is additionallyprovided, because both during transportation and during their use at theconstruction site, the screws can not fall out of the tubular extensionsof the large-area washers.

BRIEF DESCRIPTION OF THE DRAWINGS

Additional inventive characteristics and special advantages are furtherexplained in the following description with reference to the drawingswherein:

FIG. 1 shows a section through a washer with tubular extension along theline 1—1 in FIG. 2;

FIG. 2 shows a top view of a large-area washer;

FIG. 3 shows a section along line 3—3 in FIG. 2;

FIG. 4 shows a longitudinal section through a large-area washer withtubular extension, in which the large-area washer is of substantiallycircular form;

FIG. 5 shows a section through several fixing elements in which screwsare preassembled in the tubular extension of the large-area washers,with the fixing elements connected to each other in the manner of anscrew strip;

FIG. 6 shows a top view of the screw strip according to FIG. 5;

FIG. 7 shows a section through a fixing element upon pre-insertion in aninsulating strip or plate with an additional sealing strip.

DETAILED DESCRIPTION OF THE INVENTION

The drawings show two different embodiments of large-area washers,namely washers of elongated shape on the one hand, and washers ofcircular shape on the other hand. However, the configuration of thewashers 2 has no bearing on the present invention, so that thedescription also does not differentiate between them in this regard.Basically, all possible shapes are available. Thus, it is also possibleto manufacture the large-area washer 2 and an extension 3 connected toit as separate components, which are subsequently joined firmly togetheror else are interlocked by interlocking shapes or friction. The washers2 as well as their tubular extension 3 are usually made of plastic. Itis also possible to make the tubular extension 3 of plastic and thelarge-area washer 2, of metal, for example.

The fixing element 1 consists of a large-area washer 2 having a tubularextension 3 and a screw 4. By means of such a fixing element 1,insulating strips 5 or plates and potentially additional sealing strips6 are to be fixed on a solid substructure. The screw 4 is provided witha thread 9 over at least a portion of the length of its shaft 8, aboring portion 10 being formed at the free end of the screw 4 forpenetration into the substructure 7. At the other end, the screw 4 has ascrew head 11, whose top side 12 is lens-shaped. The underside 13 of thescrew head is shaped like a truncated cone.

The tubular extension 3 has, at least over a large segment of itslength, an inner cross-section sufficiently large for the rotationalreception and axial displacement of the screw head 11, i.e. anappropriately large diameter D. At the end of the tubular extension 3facing away from the washer 2 there is formed an end segment 14 with apass-through opening, which permits passage of the shaft 8 of screw 4 orof the thread 9 on shaft 8.

In the segment of the tubular extension 3 in which the screw head 11 isaxially displaceable, there is provided a rib 15 which extends radiallyinward into the slidable region, and which limits the range of movementof the screw head 11. During preassembly of screw 4 in the tubularextension 3, the screw head 11 is pushed downwardly across rib 15 in thedirection toward the free end of the tubular extension 3. As soon as thescrew head 11 has surmounted the obstacle formed by rib 15, rib 15 formsan abutment for the screw head 11 oriented against the screwing-indirection. In other words, the screw is restrained inside the tubularextension 3 oppositely to the screwing-in direction.

The preassembly is performed by appropriate tools or instruments suchthat the force required to overcome the projecting rib 15 presents noproblem. Since the tubular extension 3 customarily consists of plastic,the rib 15 is elastically depressed during pushing-past of the screwhead 11. This is also promoted by shaping the underside of the screwhead as a truncated cone transition. Thus it is quite possible that rib15 extends in continuous circumferentially closed form around the entireportion of the interior wall.

Rib 15 is formed approximately in the middle of the length of thetubular extension. Depending on the length of screw 4, or depending onthe desired telescoping capability between the tubular extension 3 andthe screw 4, rib 15 can be formed either nearer to the free end oftubular extension 3, or nearer to the large-area washer 2. However, caremust be taken that the distance A of rib 15 from the free end of tubularextension 3 is smaller than the overall length L of the screw includingthe boring portion 10 formed at its free end. This ensures that at leastthe boring portion 10, but also portions of shaft 8 bearing thread 9,will protrude beyond the free end of tubular extension 3.

If a fixing element 1 of the preassembled type shown in FIG. 7 isavailable, the large-area washer 2 can be grasped by hand, for example,and then the boring portion 10 and with it also an appropriatecorresponding segment of shaft 8 of screw 4, can be pushed into thesealing strip 6 and the insulating strip 5 by pressing downwardly in thedirection of arrow 16. This enables pre-insertion of the fixing element1 and its ultimate setting thereof by means of a driving-in tool. Duringpushing-in, rib 15 forms an abutment for screw head 11, so that theforce exerted during pushing down on the large-area washer 2 istransmitted to the screw head 11 and with it also to the free end ofscrew 4. A preassembled fixing element 1 can also be processedadvantageously in a setting machine. In that case, the projecting screwcan sometimes be pushed into the substructure even before thescrewdriver bit is operatively connected to the screw.

Such fixing elements 1 are preferably already preassembled during theirmanufacture, by inserting screws 4 into the tubular extension 3 of thelarge-area washers 2. By the application of appropriate force, the screwhead 11 can be pushed past the constriction formed by rib 15, whereuponrib 15 serves as abutment for the screw head in one direction ofmovement. Nevertheless, a telescope-like movement is possible betweenscrew 4 and the tubular extension 3. By virtue of this, handling duringpre-insertion is substantially improved, and loss prevention for thescrew is also provided.

From FIGS. 5 and 6 it can be seen that several fixing elements can beconnected to each other either contiguously or following each other at asmall distance, into a kind of screw strip. In the example shown, mutualconnections in the regions of large-area washers 2 are provided by webs17 or tapes.

The foregoing description always referred to a rib 15 extending radiallyinward. However, it is also entirely possible to provide more than onerib 15. In such a case, the screw head can be preassembled, for examplebetween two ribs 15, with the spacing of the ribs determining the rangeof axial movement between screw and tubular extension. Within the scopeof the invention, there also exists the possibility of utilizing,instead of ribs, merely one or more burls, which can perhaps besurmounted more easily during preassembly of the screws but whichprovide nevertheless an adequate abutment during pre-insertion of thecompleted fixing element. To facilitate pushing-in of the screw head andnevertheless make an appropriately strong abutment against reversemovement, one possible adaptation is to provide the ribs, burls or thelike with special cross-sectional shapes.

What is claimed is:
 1. A preassembled fixing element for fixinginsulation on a solid substructure, the fixing element having a screwwith a lens-shaped screw head and a shaft with a thread over at least aportion thereof, the fixing element comprising: a large-surface areawasher defining a hole; a tubular extension disposed on thelarge-surface area washer around the hole to define a passage which issufficiently large to receive the screw head therein, the tubularextension having an end segment, located opposite to the large-surfacearea washer, the end segment being configured to permit the passage ofthe shaft of the screw and to prevent the passage of the screw headtherethrough, at least one rib disposed within the tubular extension,the at least one rib protruding radially inwardly into the passage; andwherein the at least one rib is shaped and dimensioned relative to thescrew head so as to prevent the screw head from passing the at least onerib when moving toward the large-surface area washer, whereby, with thescrew head positioned between the at least one rib and the end segment,the screw is adapted to be driven into the insulation by pushing thelarge-surface area washer toward the insulation via the at least one ribcontacting the screw head.
 2. The fixing element according to claim 1,wherein the at least one rib is formed generally medially along a lengthof the tubular extension.
 3. The fixing element according to claim 1,wherein the at least one rib comprises an annular ring.
 4. The fixingelement according to claim 1, wherein the at least one rib is spacedfrom the end segment by a distance less than an overall length of thescrew.
 5. The fixing element according to claim 1, wherein the screwhead has a convex outwardly facing portion and includes a transitionbetween the convex outwardly facing portion and the shaft that has atruncated cone shape.
 6. The fixing element according to claim 1,wherein a plurality of large-surface area washers are connected to eachother and each have a tubular extension disposed thereon, the pluralityof large-surface area washers forming a screw strip.
 7. The fixingelement according to claim 1, further comprising the screw disposedwithin the fixing element with the screw head located between the atleast one rib and the end segment.